Prognostic Implications of Vancomycin Therapeutic Drug Monitoring for Critically Ill Stroke Patients: Evidence From a Subtype‐Oriented Analysis

Background Post‐stroke infections, particularly those caused by Gram‐positive pathogens, are frequent in neurocritical care and worsen outcomes. Vancomycin is widely used against severe Gram‐positive infections, and therapeutic drug monitoring (TDM) is recommended to optimize efficacy and minimize toxicity. However, its prognostic value in critically ill stroke patients remains unclear. Methods Clinical data were obtained from the MIMIC‐IV (v3.1) database. Adult patients with ischemic or hemorrhagic stroke receiving intravenous vancomycin were included. Patients were stratified by stroke subtype and TDM status. Propensity score matching (PSM) was performed to balance baseline characteristics. The primary outcome was 28‐day mortality; secondary outcomes included ICU, hospital, 60‐, 90‐, and 365‐day mortality. Results A total of 1266 patients were analyzed (543 hemorrhagic, 723 ischemic). In hemorrhagic stroke, 28‐day mortality was lower in the TDM group (24.6% vs. 48.2%, p < 0.001), and the association persisted after PSM (23.3% vs. 40.8%, p = 0.007). Multivariable Cox analysis confirmed TDM as an independent predictor of reduced 28‐day mortality (adjusted HR = 0.29, 95% CI 0.15–0.56, p < 0.001). No significant association was observed in ischemic stroke. Conclusions Vancomycin TDM was independently linked to improved survival in hemorrhagic but not ischemic stroke, supporting individualized antimicrobial optimization in neurocritical care.